Flue-boiler.



A. E. WINGRDH..

FLUE BOILER.

APPLICATION FILED JULY 7.1913.

Patented Oct. 10, 1916.

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AXEL EMIL WINGRDH, or KARPALUND, SWEDEN.

FLUE-BOILER.

Specication of Letters Patent.

Patented oct. 10, 1916.

Application filed July 7, 1913. Serial No. 777,658.

To all whom t may conce-rn.'

Be it known that I, AXEL EMIL WING- RDH, a subject of the King of Sweden, and resident of Karpalund, in the Kingdom of Sweden, have invented certain new and useful Improvements in Flue-Boilers, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to an improvement in steam boilers provided with one or more flues and a screw-shaped body located in the flue, in the longitudinal direction of same, the said body having for its object to produce a spiral-shaped movement of the gases, several advantages ensuing therefrom. It is already known to provide in the screwshaped body a hollowness extending longitudinally of the same and from which smaller channels extend to the surface of the body of the screw for the introducing of secondary combustion air or other gaseous or liquid substances into the flue.

In order to avoid the overheating of the screw-shaped body, transverse outlet channels have been provided extending from the longitudinal channel to the surface of the screw. According to this invention, the said air outlet passages extend at an angle from the air admitting channel to the surface of the flanges of the screw-shaped body, and are inclined outwardly and forwardly, whereby the air is united with the gases, but the draft is not impaired or retarded.

Figure 1. of the accompanying drawing shows schematically the said device. Fig. 2 shows a part of the flue in a longitudinal section and on a greater scale. Fig. 3 is a cross section of the flue.

In the flue l, the screw-shaped body 2 is provided, made of fireproof material. In the said body 2 the central tube 3 is provided, which extends longitudinally of the body. The said tube is closed at its fore end and communicates at its rear end with an air admitting tube 4 located in the ash pit of the fire box, the said communication being effected by a fire-proof tube. The outer end of the said tube 4 is outside the shutter of the ash pit provided with a cock, valve or damper for the control of the admitted air. From the tube 3 a plurality of narrow tubes or openings 5 extend through the flanges of the screw-shaped body 2, which openings are distributed in a suitable manner on the body 2 longitudinally and circumferentially of the same. The air passes through the said tubes or openings into the gases passing through the liuc l. The air may, evidently also enter the tube 3 at the fore end of the body 2, which end is opposite to the fire box, and in this case the rear end of the tube is closed. A plurality of longitudinal tubes or channels 3 with appertaining admitting tubes 4 and lateral outlet openings 5 may also be provided in the body 2. By the arrangement described above the secondary air can, consequently, pass through the parts of the screw-shaped body located farther from the center and cool the same. i

I claim as my invention 1. In a steam boiler, the combination with a fiue, a screw-shaped body provided in said flue and extending longitudinally of the same, a longitudinal air admitting channel provided in said screw-shaped body, air outlet channels extending at an angle from the said air admitting channel to the surface of the flanges of the screw-shaped body, said air outlet channels inclining outwardly and forwardly whereby the air is mixed with the gases but the draft is not impaired.

2. In a steam boiler, the combination with a flue, a screw-shaped flanged body extending longitudinally in said flue and provided with an air admitting channel and air outlet channels angularly disposed in said screw-shaped body and extending for- -wardly and outwardly from said air admitting channel to the surface of the flanges.

In witness whereof, I have hereunto signed my name in the presence of two subscribing witnesses. y e

AXEL EMIL WINGARDH. Witnesses:

E. HEDENSKAG, A. LARsoN.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents. Washington, D. C. 

